Flotation of minerals



is I

UNITED STATES PATENT oFFlcE ASSIGNORS 'IO METALS RECOVER? COMPANY, OF NEW YORK,-

RATION OF MAINE.

N. 'Y., A c0330- FLOTA'IION OF MINERALS.

No Drawing.

To all whom it may concern:

Be it known that we, CLEMENT L. Pim- KINS and RALPH E. SAYRE, citizens of the United States, residing at Pittsburgh, Allegheny county, State of Pennsylvania, have invented certain new and useful Improvements in Flotation of Minerals; and we do hereby declare the following to be a full, clear, and exact description of the lnventlon,

such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the concentration of minerals, such as sulfid ores and the like, by flotation, and is based upon the dis covery that improved results can be obtained by carrying out the flotation operation with the addition to the ore or mineral pulp of. organic compounds containing sulfur and nitrogen, particularly sulfur derlvatives of compounds containing reduced n1- trogen. Organic sulfur-nitrogen compounds which have been 'found eflectlve in the flotation of minerals include thio-ureas, thiocyanogen compounds, thio-amido compounds or sulfur derivatives of amins, amido-thiophenols, as well as certain other compounds belonging to other groups.

' Among the organic nitrogen-sulfur compounds which can thus be used may be men.- tioned the following:

Diphenyl-thiourea, (thio carbanilid,)

Monophenyl-thiourea,

Di-o-tolyl-thiourea,

Di-p-tolyl-thiourea,

Di-xylyl-thiourea,

, Phenyl-iso-thiocyanate, Thioanilin, (p-diamido-diphenyl sulfid,)

Dehydro-thio-p-toluidin,

-' Dehydro-thio-o-toluidin,

Dithio-diphenyl amin,

Diphenyl-thio-carbazid,

Thiuram-disulfid,

Thialdin,

Carbothialdin,

Amino-thio-phenol,

Diamino-phenyl-disulfid. I

These various organic substances all contain nitrogen and sulfur. Their methods of description. However, the compoundsneed 7 not, in many cases, be isolated in a state of purity but may be used in an impure stateor accompanied with such by-products as are Specification of Letters Patent. .14 Application filed November 11, 1919. Serial naeazsa'aj I formed at the same time. Thus, for example, where the thio compounds of amins or of the sulfur-nitrogen compounds as such in t a state of purity. The compound thus pro duced may in fact be accompanied by byproducts or by unchanged nitrogenous compounds which act as a solvent for the compounds produced or which themselves contrlbute to the value of the product in the flotation process. An effective flotation agent may thus be made by boiling toluidin with sulfur and the resulting product may be used, without further purification, in the flotation process.

The valuable properties of man' "if not all, of the organic nitrogen-sul r compounds above referred to appears to be re lated to the fact that these compounds are in a reduced state rather than in an oxidized state.

In carrying out the flotation process, the flotation agent or agents may be incorporated with the ore or mineral pulp in any suitable manner, for example, by introduction into the tube mill in which the ore is bemg ground, or by mixing or digesting with water and addingthe resulting product to the ore pulp just before it enters the flotation apparatus, or by dissolving the flotat1on agent (where it is not itself readily incorporated with the mineral pulp) in an organic solvent therefor, or in one of the usual flotation oils or oil mixtures, and incorporating the resulting solution with the ore pulp,

or in other suitable manner which willinsure the uniform dissemination of the flotafrothing qualities.

After the flotation agent or agents have been thoroughly and uniformly distributed throughout the ore pulp, the resulting mixture is subjected to a flotation operation, as

inan ordinary Gallow cell or other pneumatic flotation cell, or in apparatus where the air is incorporated in the ore pulp by mechanical agitation.

The action of the flotation a ents' above referred to is suflicientlymarke so that but a small amount thereof will usually be required, for example, with many of these agents, as littleas one-fifth of a pound per of alkali, such as sodium hydroxid or lime, which can be incorporated with the OIGPlllPy in any suitable manner, as by grinding therewith in the usual mill. The amount of alkali may be, for example, two pounds of caustic soda per ton of ore.

a The invention will be further illustrated by the following specific example of a test made u on a so-called porphyry ore of the Utah opper Company which'is a copper sulfid ore having a silicious gangue and containing its floatable or sulfid copper in the form of a mixture of chalcocite and chalcopyrite. In general, treatment of the ore with alkalis, as above noted, gives improved results, the 'alkalis themselves apparently having a valuable effect in improving the flotation process. 7

Five hundred parts' by weight of the ore was ground in a pebble mill with two h m dred and fifty parts of water, sodiumhydroxid equivalent to two pounds per ton of dry ore, and dehydro-thio-p-toluidin equivs alent to one-fifth pound per ton. The

ground pulp was then transferred to a Callow rougher cell and subjected. to flotation with the addition of about one-tenth duces a relatively voluminous froth but has very little tendency to float the sulfid in the ore when used by itself. The heads from this test contained 1.39% copper; the con centrate produced contained about 23% copper; and the recovery was about'74.5%. j

Better recoveries have been obtainedwith somewhat larger amounts of dehydro-thiop-toluidin, for example, one test using" one pound per ton gave a 16.4% concentrate and 87.3% recovery. I In the above example, lime, in the same or somewhat larger proportions, may be sub stituted for sodium hydroxid. So also, other suitable frothing agents maybe sub- 65. stituted for the terpineol.

i Dehydro thiop-toluidinis one of the sulfur derivatives 'of amin's. ,It maybe made by prolonged heating of 'p-toluidin with sulfur. 7 It is a crystalline solid and is commonly regarded as insoluble. It jmay be advantageously incorporated T with the ore pulp by. adding the finely powdered dry compound to the ore pulp in the grinding mill. It may also; be dissolved in appropriate organic solvents therefor, particularly those which have good frothing qualities and which will contribute to the carrying out of the flotation operation, for example xylidin, or other suitable amins'.

In our com anion application Serial No. 284,981, filed arch 25, 1919, we have described and claimed the improved flotation process in which thin-urea compounds or substances, and specifically vthio-carbanilid, are employed, and such process accordingly is not claimed specifically herein, although it is included within the more comprehensive claims'appended hereto, but the more specific'claims of the present case are directed. to the process in which thio-amido compounds, and specifically dehydro-thiop-toluidin, are employed. So also, while certain of the organic nitrogen-sulfur compounds above referred to are substantially" non-'frothing collecting or mineral modify ing agents, no claim is made herein to the process in which such agents generall are employed, inasmuch as such process orms the subject matter of an application of one of; 9

1919; but the claims-of the present case are}? directed to the process in which organic nitrogen-sulfur compounds of the character above described are employed, irrespective of whether such compounds are substantially non-frothing, or have frot-hing, as well as mineral modifying properties. The process of the present invention is also distinguished from the process in which salts of amido compounds are employed, such as sulfates, which contain ,sulfur in the acid radical of the salts, as set forthfiin the a v plication of one of us, (Perkins) Serial 0. pound of terpineol per ton. Terpineol pro-f the organic nitrogen-sulfur compounds and are themselves supplemented in their action by such compounds. The action of many of the organicnitro gen-sulfur compounds in the flotation process appears to be a selective action upon the marked so that it is possible to raise relatively large mineral panticles and hence fine grindmg' becomes of lessunportance.

We cla1m:

1. The method of effecting the concentra tion of minerals by flotation, which comprises adding to the mineral pulp. a small amount of an organic nitrogen-sulfur compound, and subjecting the resulting mixture to a flotation operation; substantially as described.

2. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of a sulfur derivative of 'a compound containing reduced nitrogen, and subjecting the resulting mixture to a flotation operation; substantially as described.

3. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of an organic thio-amido compound,

and subjecting the resulting'mixture to a flotation I operation; substantially as de scribed.

4. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of dehydro-thio-p-toluidin. and subjeeting the "resulting mixture to a flotation operation; substantially as described.

5. The method of effecting the concentra tion of minerals by flotation, which com-' prises adding to the mineral pulp a small amount of an organic nitrogen-sulfurcompound, together with an agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation; substantially as described.

6. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of a sulfur derivative of an organic compound containing reduced nitrogen, together with an agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation; substantially as described.

7. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of an organic thio-amido compound,

together with an agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation; substantially as described. a

8. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of dehydro-thio-p -toluidin, together withv an agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation substantially as described.

9. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of an organic nitrogen-sulfur com pound in an organic solvent therefor, and subjectingthe resulting mixture to a flotation operation; substantially as described.

10. The method of effecting the concentra:

.tion of minerals by flotation, which comprises adding to the mineral pulp a small amount of an organic nitrogen-sulfur compound, together with a small amount ofalkali, and subjecting the resulting mixture to a flotation operation; substantially as described.

11. The method of effecting the concentration of minerals by flotation, which comprises adding to the'mineral pulp a small amount of an organic nitrogen-sulfur compound, together with a small amount of alkali and an agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation; substantially as described.

12. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of a sulfur derivative of an organic compound containing reduced nitrogen together with a small amount of alkali, and subjecting the resulting mixture to a flotation operation; substantially as described.

13. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of a sulfur derivative of an organic compound containing reduced nitrogen together with a small amount of alkali and an agent having good frothing qualities; and subjecting the resulting mixture to a flotation 0 eration; substantially as described.

1.4. he method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of a sulfur derivative of an organic amido compound, together with a small amount of alkali and of an agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation; substantially as described.

15. The method of effecting the concentra' tion of minerals by flotation, which comprises adding to the mineral pulp a small amount of dehydro-thio-p-toluidin, together with a small amount of alkali and of an agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation; substantially as described.

In testimony whereof we affix our signatures.

CLEMENT L. PERKINS. RALPH E. SAYRE. 

